The present invention is directed to bicycles and, more particularly, to a bicycle disk brake pad.
Disk brake pads normally pinch a disk brake rotor that rotates along with the wheel in order to brake the wheel. Resin pads are examples of conventional disk brake pads. Such pads are shown in Japanese Unexamined Patent Application (Kokai) 6-74267, for example. As shown in that reference, resin pads may comprise a backing plate and a friction member attached to the backing plate by an adhesive. The friction member may comprise several powdered elements, sometimes including brass, joined together by a synthetic resin binder. It is also known to form disk brake pads wherein the friction member is formed from sintered materials. For example, a sintered friction member typically used with rotors made from iron, cast iron or stainless steel may comprise a foundation of Cu of Fe powder mixed with Sn, Zn powder, graphite, MOS2, and a hard material such as SiO2 and/or Al2O3. A sintered friction member typically used with rotors made from titanium or titanium alloy is disclosed in U.S. Pat. No. 5,922,452. That friction member comprises a foundation of titanium or titanium alloy powder, a powder such as Al, Ni, Co, Fe, Mn, Cu, V or Zr for abrasion resistance, a solid lubricant, and a hard material fiber such as mullite. Such a pad improves heat resistance and abrasion resistance relative to sintered pads formed from a foundation of Cu or Fe.
One difficulty with sintered friction members formed from titanium or titanium alloy is that the titanium material is lighter than the other metallic materials, and there is a risk that the titanium does not mix uniformly with the other metallic materials. This can adversely affect braking characteristics and produce variations of braking characteristics from one pad to another, thereby affecting quality control.